With the help of Shared libraries with GCC on Linux I tried to make libadd1.so and succeeded. The code runs perfectly.
But when I tried the same thing using dlopen() and dlsym() I got errors as shown below.
$ g++ -L/home/shreya/Desktop/soFiles -Wall -o test main.c -ladd1
main.c: In function ‘int main()’:
main.c:14:14: warning: variable ‘ptrVar’ set but not used [-Wunused-but-set-variable]
pt2function ptrVar;
^
/tmp/ccpdIje6.o: In function `main':
main.c:(.text+0x19): undefined reference to `dlopen'
main.c:(.text+0x29): undefined reference to `dlerror'
main.c:(.text+0x54): undefined reference to `dlerror'
main.c:(.text+0x68): undefined reference to `dlsym'
main.c:(.text+0x71): undefined reference to `dlerror'
main.c:(.text+0x1ca): undefined reference to `dlclose'
collect2: error: ld returned 1 exit status
$
Can any one tell me what's wrong?
See the manpage. For Linux, you have to link with -ldl for using the dynamic linking functions. This is a bit of a hassle because e.g. on FreeBSD, they are part of the standard library.
BTW, linking the library that you want to open dynamically (in your case -ladd1) doesn't make sense.
Related
I am trying to follow some sqlite C++ tutorial to be able to access a database from within C++ code on Linux. sqlite3 is installed and working, but when I try to compile the example code given on the link (Create a Table) I get the following error:
g++ build/test.o -o bin/test -pthread -L lib
build/test.o: In function `main':
/home/alexander/Projects/Test/src/test.cpp:22: undefined reference to `sqlite3_open'
/home/alexander/Projects/Test/src/test.cpp:24: undefined reference to `sqlite3_errmsg'
/home/alexander/Projects/Test/src/test.cpp:39: undefined reference to `sqlite3_exec'
/home/alexander/Projects/Test/src/test.cpp:42: undefined reference to `sqlite3_free'
/home/alexander/Projects/Test/src/test.cpp:46: undefined reference to `sqlite3_close'
collect2: error: ld returned 1 exit status
Do I need to install something else? Or do I need to set some paths?
I have no practice in compiling straight from the shell.
In CodeBlocks it is necessary to point the paths of the “sqlite3.h” header and the “libsqlite3.so” dll.
If the dll is not specified in Linker Settings, exactly the mentioned problem occurs.
I am trying to link libevent using g++ but am having trouble since I set libevent's install directory with the --prefix flag when configuring. To install libevent I downloaded the latest source, extracted it and ran the following commands in the directory
./configure --prefix=/home/tom/local --disable-shared && make
make install
After running these commands libevent successfully installs to the /home/tom/local folder. Now to test that I can use libevent I have downloaded the sample rot13 server with libevent that can be found towards the bottom of: http://www.wangafu.net/~nickm/libevent-book/01_intro.html
To compile I run the following command:
g++ -I=/home/tom/local/include rot13server.cpp -L/home/tom/local/lib
But I get the following compilation errors:
/tmp/cctwJY4k.o: In function `alloc_fd_state(event_base*, int)':
libevent.cc:(.text+0x9b): undefined reference to `event_new'
libevent.cc:(.text+0xec): undefined reference to `event_new'
libevent.cc:(.text+0x11a): undefined reference to `event_free'
/tmp/cctwJY4k.o: In function `free_fd_state(fd_state*)':
libevent.cc:(.text+0x1b6): undefined reference to `event_free'
libevent.cc:(.text+0x1c9): undefined reference to `event_free'
/tmp/cctwJY4k.o: In function `do_read(int, short, void*)':
libevent.cc:(.text+0x310): undefined reference to `event_add'
/tmp/cctwJY4k.o: In function `do_write(int, short, void*)':
libevent.cc:(.text+0x4da): undefined reference to `event_del'
/tmp/cctwJY4k.o: In function `do_accept(int, short, void*)':
libevent.cc:(.text+0x564): undefined reference to `evutil_make_socket_nonblocking'
libevent.cc:(.text+0x5da): undefined reference to `event_add'
/tmp/cctwJY4k.o: In function `run()':
libevent.cc:(.text+0x5f3): undefined reference to `event_base_new'
libevent.cc:(.text+0x63f): undefined reference to `evutil_make_socket_nonblocking'
libevent.cc:(.text+0x6d2): undefined reference to `event_new'
libevent.cc:(.text+0x6e7): undefined reference to `event_add'
libevent.cc:(.text+0x6f3): undefined reference to `event_base_dispatch'
collect2: error: ld returned 1 exit status
It seems like the compiler is finding the include files but not the object files.
I also tried configuring libevent without the --disable-shared option and then exported /home/tom/local/lib to the LD_LIBRARY_PATH but I still get the same error with the compile command:
g++ -I=/home/tom/local/include rot13server.cpp
Can anyone tell me what I am doing wrong?
Thanks
Can anyone tell me what I am doing wrong?
Just about everything.
The -I=/home/tom/local/include tells GCC to look in =/home/tom/local/include directory, which is unlikely to exist.
You want:
g++ -I/home/tom/local/include rot13server.cpp -c
g++ -L/home/tom/local/lib rot13server.o -levent -o rot13server
When I've try to compile program (test for my lib) I've got undefined reference of for every called method. I've read answers on "gcc undefined reference to", but it has not help.
PS I using: Debian 7.2.0 and C++11 standart.
#include <RFw/String.hpp>
#include <stdio.h>
using namespace RFw;
int main() {
Array<char> _arr_ (5);
_arr_[0] = 'b';
_arr_[1] = 'c';
printf("%c%c\n", _arr_[0], _arr_[2]);
printf(RFw::getVersion());
return 0;
}
Makefile target:
test:
c++ test.cpp -I./include-core/ -o bin/test -L./bin -l${core_NAME_ROOT}
Console output:
test.cpp:13:9: warning: format string is not a string literal (potentially insecure) [-Wformat-security]
printf(RFw::getVersion());
^~~~~~~~~~~~~~~~~
1 warning generated.
/tmp/test-lxdZF4.o: In function `main':
test.cpp:(.text+0x20): undefined reference to `RFw::Array<char>::Array(int)'
test.cpp:(.text+0x33): undefined reference to `RFw::Array<char>::operator[](int)'
test.cpp:(.text+0x54): undefined reference to `RFw::Array<char>::operator[](int)'
test.cpp:(.text+0x75): undefined reference to `RFw::Array<char>::operator[](int)'
test.cpp:(.text+0x99): undefined reference to `RFw::Array<char>::operator[](int)'
test.cpp:(.text+0xff): undefined reference to `RFw::Array<char>::~Array()'
test.cpp:(.text+0x11a): undefined reference to `RFw::Array<char>::~Array()'
./bin/libregemfw0.1-core.so: undefined reference to `RFw::Array<char>::operator[](int) const'
./bin/libregemfw0.1-core.so: undefined reference to `RFw::Array<char>::Array(int)'
./bin/libregemfw0.1-core.so: undefined reference to `RFw::Array<char>::getLength() const'
./bin/libregemfw0.1-core.so: undefined reference to `RFw::Exception::onThrow()'
./bin/libregemfw0.1-core.so: undefined reference to `RFw::Array<char>::resize(int)'
./bin/libregemfw0.1-core.so: undefined reference to `RFw::Array<char>::addElementOnEnd(char)'
./bin/libregemfw0.1-core.so: undefined reference to `vtable for RFw::Object'
./bin/libregemfw0.1-core.so: undefined reference to `typeinfo for RFw::Object'
./bin/libregemfw0.1-core.so: undefined reference to `RFw::Object::~Object()'
./bin/libregemfw0.1-core.so: undefined reference to `RFw::Array<char>::~Array()'
clang: error: linker command failed with exit code 1 (use -v to see invocation)
make: *** [test] Ошибка 1
The problem is that
c++ test.cpp -I./include-core/ -o bin/test -L./bin -l${core_NAME_ROOT}c++ test.cpp -I./include-core/ -o bin/test -L./bin -l${core_NAME_ROOT}
will first process the library and then your .cpp file. When processing a library, referenced symbols are resolved ("linked") and all unresolved symbols in the library that aren't needed are thrown away. That means that as soon as your .cpp file is being processed, these symbols are already rejected. You have the library twice in your command line, but the second one is being ignored since the library was already processed.
You should always put the libraries (once) at the end of the compiler command line:
c++ test.cpp -I./include-core/ -o bin/test test.cpp -L./bin -l${core_NAME_ROOT}
I am driving nuts....
I'm working on a program to read out Joint Coordinates from an Xtion Primesense sensor with OpenNI and NiTE. I got the program splittet in 3 parts. Main, sensorOpenNI.hpp and sensorOpenNI.cpp. Now while linking the parts together I get lots of errors saying there are undefined references to some NiTE functions. I'm working with Kubuntu and g++. The NiTE and OpenNI libs are in a directory called Include...
Here's the error message:
/tmp/ccrPQHEg.o: In function openni::VideoFrameRef::release()':
sensorOpenNI.cpp:(.text._ZN6openni13VideoFrameRef7releaseEv[openni::VideoFrameRef::release()]+0x18): undefined reference tooniFrameRelease'
/tmp/ccrPQHEg.o: In function openni::VideoFrameRef::_setFrame(OniFrame*)':
sensorOpenNI.cpp:(.text._ZN6openni13VideoFrameRef9_setFrameEP8OniFrame[openni::VideoFrameRef::_setFrame(OniFrame*)]+0x25): undefined reference tooniFrameAddRef'
/tmp/ccrPQHEg.o: In function nite::UserTrackerFrameRef::release()':
sensorOpenNI.cpp:(.text._ZN4nite19UserTrackerFrameRef7releaseEv[nite::UserTrackerFrameRef::release()]+0x24): undefined reference toniteUserTrackerFrameRelease'
/tmp/ccrPQHEg.o: In function nite::UserTracker::create(openni::Device*)':
sensorOpenNI.cpp:(.text._ZN4nite11UserTracker6createEPN6openni6DeviceE[nite::UserTracker::create(openni::Device*)]+0x13): undefined reference toniteInitializeUserTracker'
sensorOpenNI.cpp:(.text._ZN4nite11UserTracker6createEPN6openni6DeviceE[nite::UserTracker::create(openni::Device*)]+0x27): undefined reference to niteInitializeUserTrackerByDevice'
/tmp/ccrPQHEg.o: In functionnite::UserTracker::destroy()':
sensorOpenNI.cpp:(.text._ZN4nite11UserTracker7destroyEv[nite::UserTracker::destroy()]+0x1e): undefined reference to niteShutdownUserTracker'
/tmp/ccrPQHEg.o: In functionnite::UserTracker::readFrame(nite::UserTrackerFrameRef*)':
sensorOpenNI.cpp:(.text._ZN4nite11UserTracker9readFrameEPNS_19UserTrackerFrameRefE[nite::UserTracker::readFrame(nite::UserTrackerFrameRef*)]+0x1d): undefined reference to niteReadUserTrackerFrame'
/tmp/ccrPQHEg.o: In functionnite::UserTracker::startSkeletonTracking(short)':
sensorOpenNI.cpp:(.text._ZN4nite11UserTracker21startSkeletonTrackingEs[nite::UserTracker::startSkeletonTracking(short)]+0x1e): undefined reference to niteStartSkeletonTracking'
/tmp/ccrPQHEg.o: In functionnite::NiTE::initialize()':
sensorOpenNI.cpp:(.text._ZN4nite4NiTE10initializeEv[nite::NiTE::initialize()]+0x7): undefined reference to niteInitialize'
collect2: ld returned 1 exit status
patrick#ubuntu:~/Koerpersteuerung$ g++ -c sensorOpenNI.cpp sensorOpenNI.hpp -I Include/
patrick#ubuntu:~/Koerpersteuerung$ g++ mainSensor.cpp sensorOpenNI.o -I Include/
sensorOpenNI.o: In functionopenni::VideoFrameRef::release()':
sensorOpenNI.cpp:(.text._ZN6openni13VideoFrameRef7releaseEv[openni::VideoFrameRef::release()]+0x18): undefined reference to oniFrameRelease'
sensorOpenNI.o: In functionopenni::VideoFrameRef::_setFrame(OniFrame*)':
sensorOpenNI.cpp:(.text._ZN6openni13VideoFrameRef9_setFrameEP8OniFrame[openni::VideoFrameRef::_setFrame(OniFrame*)]+0x25): undefined reference to oniFrameAddRef'
sensorOpenNI.o: In functionnite::UserTrackerFrameRef::release()':
sensorOpenNI.cpp:(.text._ZN4nite19UserTrackerFrameRef7releaseEv[nite::UserTrackerFrameRef::release()]+0x24): undefined reference to niteUserTrackerFrameRelease'
sensorOpenNI.o: In functionnite::UserTracker::create(openni::Device*)':
sensorOpenNI.cpp:(.text._ZN4nite11UserTracker6createEPN6openni6DeviceE[nite::UserTracker::create(openni::Device*)]+0x13): undefined reference to niteInitializeUserTracker'
sensorOpenNI.cpp:(.text._ZN4nite11UserTracker6createEPN6openni6DeviceE[nite::UserTracker::create(openni::Device*)]+0x27): undefined reference toniteInitializeUserTrackerByDevice'
sensorOpenNI.o: In function nite::UserTracker::destroy()':
sensorOpenNI.cpp:(.text._ZN4nite11UserTracker7destroyEv[nite::UserTracker::destroy()]+0x1e): undefined reference toniteShutdownUserTracker'
sensorOpenNI.o: In function nite::UserTracker::readFrame(nite::UserTrackerFrameRef*)':
sensorOpenNI.cpp:(.text._ZN4nite11UserTracker9readFrameEPNS_19UserTrackerFrameRefE[nite::UserTracker::readFrame(nite::UserTrackerFrameRef*)]+0x1d): undefined reference toniteReadUserTrackerFrame'
sensorOpenNI.o: In function nite::UserTracker::startSkeletonTracking(short)':
sensorOpenNI.cpp:(.text._ZN4nite11UserTracker21startSkeletonTrackingEs[nite::UserTracker::startSkeletonTracking(short)]+0x1e): undefined reference toniteStartSkeletonTracking'
sensorOpenNI.o: In function nite::NiTE::initialize()':
sensorOpenNI.cpp:(.text._ZN4nite4NiTE10initializeEv[nite::NiTE::initialize()]+0x7): undefined reference toniteInitialize'
collect2: ld returned 1 exit status
I'm calling g++ like this:
g++ -o test mainSensor.cpp sensorOpenNI.cpp -I Include/
Try copying the libraries libOpenNI2.so and libNiTE2 like that:
sudo cp ./OpenNI-Linux-x86-2.2/Redist/libOpenNI2.so /usr/local/lib
sudo cp ./NiTE-Linux-x86-2.2/Redist/libNiTE2.so /usr/local/lib
then do
sudo ldconfig
and now compile the program by adding -lOpenNI2 -lNiTE2
I am trying to use Goblin library which is used for special network algorithms. This library provides some header files and objects in C/C++. So, you can easily add a header file to your program and use some special classes and functions.
Unfortunately, when I add the header file, I get error. In the following you can see the simple code and error.
Source:
#include<goblin.h>
int main()
{
return 0;
}
Error:
$ g++ -o test.o test.cpp
/tmp/ccB0Rb25.o: In function `goblinRootObject::~goblinRootObject()':
test.cpp:(.text._ZN16goblinRootObjectD1Ev[goblinRootObject::~goblinRootObject()]+0x10): undefined reference to `goblinNObjects'
test.cpp:(.text._ZN16goblinRootObjectD1Ev[goblinRootObject::~goblinRootObject()]+0x18): undefined reference to `goblinNObjects'
test.cpp:(.text._ZN16goblinRootObjectD1Ev[goblinRootObject::~goblinRootObject()]+0x2c): undefined reference to `goblinRootObject::operator delete(void*)'
/tmp/ccB0Rb25.o: In function `goblinRootObject::~goblinRootObject()':
test.cpp:(.text._ZN16goblinRootObjectD0Ev[goblinRootObject::~goblinRootObject()]+0x10): undefined reference to `goblinNObjects'
test.cpp:(.text._ZN16goblinRootObjectD0Ev[goblinRootObject::~goblinRootObject()]+0x18): undefined reference to `goblinNObjects'
test.cpp:(.text._ZN16goblinRootObjectD0Ev[goblinRootObject::~goblinRootObject()]+0x2c): undefined reference to `goblinRootObject::operator delete(void*)'
collect2: ld returned 1 exit status
try:
g++ -lgoblin -L/pathToLibgoblin/ -o test.o test.cpp